Articles such as produce ideally should be packaged in containers which protect the contents against bruising or other damage during shipment and handling. They should also present an appealing appearance so that they can be used as retail packages after reaching their final destination, and should be economical as well.
One type of container used for this purpose is comprised of rigid end panels about which a flexible cover sheet is wrapped in order to form the bottom, side and top panels. The end panels include stacking projections on their upper or lower edges and stacking recesses on their opposite edge. When the containers are stacked, the projections from one container fit into the recesses of the next higher or lower container. The flexible sheet includes slots for receiving the stacking projections and the corners of the end panels. Means are also provided on the end panels for holding the ends of the sheet in place. Typically, the ends of the sheet may overlap to form a fully enclosed container or they may be spaced from each other to provide a partially open top panel. Depending on the weight of the contents of the containers, the number of containers stacked on a pallet and the force applied when strapping or stretch wrapping the containers onto a pallet, the strength requirements of the side panels of the containers will vary. For certain applications the side walls formed from cover sheets of conventional thickness sometimes become bowed or crushed. The normal response to correct this situation is to increase the caliper of the cover sheets. This also increases the caliper of the bottom panel, even though the strength of the bottom panel may already be adequate. It may also require different container designs in order to meet different strength objectives, which in turn requires an expensive inventory of different cutting dies for producing the various cover sheets used to form the bottom and side panels.
A main object of this invention is to provide a container which makes use of the basic design concept described above, but which can be modified according to the strength requirements for any individual order of containers. Another object is to provide means for maintaining the ends of the cover sheet in place which does not interfere with the ability to modify the container to meet special strength requirements.